Two shows make their long-awaited returns this week, including Legend of Korra. But meanwhile, there are dueling TV movies. In one, a space shuttle crashes into the sun with the First Lady on board, sending the Earth back to the Stone Age. In the other, nanotech turns a regular crocodile into... RoboCroc. Truly, we… »9/09/13 9:00am 9/09/13 9:00am